use-fs is a React hook that turns a folder on disk or the browser's origin private file system (OPFS) into reactive state, automatically re-rendering components when files are added, changed, or deleted. It handles directory walking, diffing, polling, permission management, and writing, all client-side with zero uploads.
Use this when building in-browser code editors, file managers, local-first apps, or any React tool that needs live-synced views of files being edited externally. It's especially valuable for desktop Chromium browsers with disk access, and cross-browser when the OPFS fallback is acceptable.